Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). LTE is designed to support mobile broadband access through improved spectral efficiency, lowered costs, and improved services using OFDMA on the downlink, SC-FDMA on the uplink, and multiple-input multiple-output (MIMO) antenna technology. In another example, a fifth generation (5G) wireless communications technology (which can be referred to as new radio (NR)) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, 5G communications technology can include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which can allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information.
However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in wireless communication technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.
In some wireless communications systems, a medium reservation protocols may be used to allow a wireless device to reserve the wireless channel such that the wireless device can transmit without interference from another device. One such medium reservation method is listen-before-talk (LBT) protocol that may include the exchange of request to send (RTS) signals and clear to send (CTS) signals. The wireless device that has data ready to transmit may first transmit an RTS signal to the intended recipient, after ascertaining the wireless channel is clear to send. The RTS signal may include a duration field that indicates the length of time for which the wireless device wants to reserve the medium. All devices that hear the RTS signal may then refrain from transmitting data for that length of time by setting their network allocation vectors (NAVs). The intended recipient may respond with a CTS signal that includes a duration field, also after ascertaining the wireless channel is clear to send. Any devices that hear the CTS signal but did not hear the RTS signal may also set their NAVs and thereby refrain from interfering with reception at the intended recipient. The transmitting device may transmit data to the intended recipient upon receiving the CTS signal.